A suicide bomber drove an explosive-laden car into the facilities of the Nigerian subsidiary of Bharti Airtel Ltd. of India at about 8am in the city of Kano, said Captain Iweha Ikedichi, who speaks for a special taskforce deployed in Kano to reduce the threat of the Islamic rebels known as Boko Haram.

The bombings blacked out a top operator's network in most of Nigeria's northern commercial hub.

The attack left an Airtel worker injured, authorities said.
It also damaged a switch station, said James Eze, an Airtel spokesperson. He said the company was still assessing how bad the damage was, but declined to comment further.

Switch stations control the regional mobile phone network and if they are seriously damaged, the entire network could go down.

An Airtel staff who spoke on condition of anonymity because he is not authorised to speak to the press said the targeted switch station covered six northern states, including Kano.

But while Airtel's network appeared to be down across Kano Sunday, calls to lines in some of the other states went through.

At about the same time as the Airtel attack, another bomber targeted the facilities of the Nigerian subsidiary of South Africa-based MTN Group, about three kilometres away.

That attack was botched by security officers who shot the bomber, causing an explosion at the company's gate, Ikedichi said.

The target of the foiled attack was MTN's switch station, said Funmilayo Omogbenigun, spokesperson for Nigeria's largest cell phone network provider.

Authorities suspect the Boko Haram sect is behind the attacks. The group is held responsible for more than 770 deaths this year alone, according to figures compiled by The Associated Press (AP).

Boko Haram's campaign of bombings and shootings has targeted mosques, churches, schools, universities and government buildings.

But, four months ago, the group broadened its scope by attacking mobile phone towers for the first time.

In September, a series of attacks damaged more than 31 towers operated by all the major mobile phone providers in the country.

Other attacks have occurred since then, further straining the one link Nigeria relies on for communication in a country with very few landlines.

While no one claimed responsibility for the attacks, the Islamist sect had threatened mobile phone companies earlier in the year, warning that they would be targeted for cooperating with the government to flush out its members.

In Nigeria, Africa's most populous country with more than 160-million people, mobile phones serve as a valuable lifeline in both cities and rural communities.

Landlines remain almost nonexistent, as the state-run telephone company has collapsed and repeated efforts to privatize it have failed. More 87-million mobile phone lines were in use in 2009, according to estimates.

"Never would we have expected that telecommunications could be targeted," said Damien Udeh, a spokesperson for the Association of Licensed Telecommunications Operators of Nigeria. "It portends a dangerous situation for everybody, especially government." – Sapa.